<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style type="text/css">
			div{
				color: red;
			}
			div{
				text-decoration: underline;
			}
		</style>
	</head>
	<body>
		<div>父元素
			<span>子元素</span>
		</div>
	</body>
</html>
